1. Field of the Invention
The present invention relates to a display unit having a touch panel and its manufacturing method, and more particularly such a display unit using organic light emitting devices and its manufacturing method.
2. Description of the Related Art
A so-called touch screen, wherein a touch panel is mounted to a display panel using a CRT (Cathode Ray Tube) or a liquid crystal is widely used in banks, stations and the like. Additionally, a compact touch screen is adopted for a PDA (Personal Digital Assistant), a portable terminal and the like.
A general touch panel used for conventional touch screens is, for example, has a structure wherein a glass substrate and a plastic film are layered. In such a touch panel, a glass substrate side is placed opposite to a display panel, so that a plastic film side becomes an operation face. In the case of a liquid crystal display panel, in order to prevent blooming phenomenon that images are distorted since the liquid crystal is transformed by getting pressure from touch panel operations, a void is provided between a glass substrate of the touch panel and the liquid crystal display panel.
Lately, a touch panel having a structure wherein two plastic films are layered (hereinafter referred to as “flexible touch panel”) has been developed, and this flexible touch panel is expected as what allows the PDA, the portable terminal and the like to become further thinner and lighter. However, such a flexible touch panel has no rigidity itself since it has no glass substrate, so that the flexible touch panel should be supported by bonding a display panel thereto. Therefore, there is a problem that the flexible touch panel cannot be provided with a void between itself and the display panel as in a touch screen of a conventional liquid crystal display panel, so that it is difficult to mount the flexible touch panel to the liquid crystal display panel.
To resolve the above problem, it is thinkable that a void is secured in the central part by fixing only four sides of the flexible touch panel on the display panel. In the case of taking such a measure for the conventional touch panel, when the plastic film is distorted or bent due to contact with a finger or a pen, distortion or bending can be restrained or recovered by the glass substrate. However, in the case of taking such a measure for the flexible touch panel, there is a problem that such distortion or bending cannot be restrained or recovered, and image quality may be lowered due to distortion or bending of the plastic film.
Meanwhile, it is thinkable to construct a touch screen by bonding the flexible touch panel to an organic light emitting display, instead of the liquid crystal display. However, so far, there has been a problem that there is no established technique by which the flexible touch panel can be bonded to a whole face of the organic light emitting display without distortion or bending of the plastic film.
Further, in a conventional organic light emitting display, a so-called can sealing structure is generally adopted. The can sealing structure is a structure wherein an adhesive is applied to the rim part of a rear panel, a sealing can made of metals or glass is bonded thereto, and a getter material such as calcium is enclosed in a space between the rear panel and the sealing can. In such an organic light emitting display having the can sealing structure, there is a problem that application to a touch screen of mobile devices particularly requiring high strength is difficult, since reducing thickness is limited and only four sides of the panel is fixed on the sealing can.